Vented mechanical device



United States Patent 3,439,963 4/1969 Hein etal.

Inventor Appl. No.

Filed Patented Assignee Bryan P. Kent Ithaca, New York 781,806

Dec. 6, 1968 Nov. 24, 1970 Borg-Warner Corporation Chicago, Illinois acorporation of Delaware VENTED MECHANICAL DEVICE 1 Claim, 1 Drawing Fig.

US. Cl

Int. Cl

Field of Search References Cited UNITED STATES PATENTS Fl6c 1/24308/187, l87.l, 1872 Primary ExaminerF red C. Mattern, Jr.

Assistant Examiner- Frank Susko Att0rneys Donald W. Banner, Lyle S.Motley, C. G. Stallings and William S. McCurry ABSTRACT: An overrunningclutch is disclosed herein providing a structure whereby a drive anddriven member are interconnected to provide a driving situationtherebetween inone direction and an overrunning situation therebetweenin the other direction. Substantial temperature gradients are createdduring operation of the clutch, particularly during the overrunningsituation. Seals are provided to retain lubricant in the bearings whichrotatably interconnect the drive and driven members of the clutch. Theclutch is provided with a vent structure to vent the bearing enclosureduring overrunning conditions.

Patented Nov. 24, 1970 llNVENTOR BRYAN PKENT BY w ATTORNEY 1 VENTEDMECHANICAL DEVICE SUMMARY OF THE INVENTION This invention relates to arotational device adapted to be mounted on a shaft wherein a firstmember is mounted on the shaft and a second member is rotatably mountedon bearings on the first member. The bearings are contained in alubricant chamber provided by seals that extend from the first to thesecond member longitudinally beyond the bearings. The first member isprovided with an annular groove in the periphery thereof and enclosedunder the bearing. A longitudinal peripheral slot is provided in thefirstmember and is circumferentially spaced from the keyway in the firstmember and extends longitudinally beyond the bearing to communicate withthe bearing enclosure to vent the enclosure.

The FIG. shows a sprag cam clutch with the novel venting structuralarrangement.

A cam clutch generally represented by the numeral is illustrated in theFIG. for the purpose ofidescribing the invention. The clutch 10includes, among other things, an inner racc member 11, an outer racemember 12, sprags l3, bearings 14 and seals 15. The inner race 11 isprovided with a shaft passage 16 adapted to receive a drive shaft 17 anda keyway 19 adapted to receive a key 20 supported in the keyway 19 andin the shaft 17 for locking the inner race 11 to the shaft. The bearings14 aresupported on an outer surface of the inner race 11 againstshoulders 26 extending radially outward. The outer race 12 is mounted onthe bearings 14 and is thereby rotatably mounted on the inner race 11and is held against longitudinal motion by rings 27 positioned ingrooves in the outer race 12. The sprags 13 are positioned between acircumferential surface 30 of the inner race 11 and an internal surface31 ofthe outer race 12 that is substantially concentric with the surface30 ofthe inner race 11.

The sprags 13 can have any one of many configurations normally utilizedin cam clutches and for purposes of illustrating this inventionthesprags are of the type which are cammed into engagement with thesurfaces 30 and 31 of the inner and outer races to provide a drivetherebetween when a load is applied to the outer race 12 and the driveshaft 17 is rotated in one direction but, which will not provide suchdrive connec tion when the drive shaft 17 is rotated in the otherdirection. ln the former, thetypical drive is provided by a cam clutchas illustrated, and in the latter, there is the typical overrunningeffect as illustrated. A lubricant (not shown) is provided for thebearings 14 and the sprags l3 and is retained by the seals 15 held inposition 'by retaining casings 32 press fitted or otherwise secured tothe inner surface 31 of the outer race 12. it should be noted that theseals 15 provide a bearing and sprag lubricant enclosure 33 for thepurpose of retaining the lubricant in the area ofthe bearings 14 andsprags 13.

The present invention has an improved venting structure in the lubricantenclosureln particular, the inner race 11 of the clutch 10 has a smallpassage 34 formed therein interconnecting a groove 35 on the outersurface 25 with a passage such as the keyway 19. The groove 35 isconnected to the lubricant enclosure 33 by a longitudinal slot 37. itshould be noted that the slot 37 is substantially circumferentiallyspaced from the passage34.

in the operation of the invention, the drive shaft 17 may be rotated inone direction to provide driving connection between the inner and outerraces 11 and 12, or it may be driven in the other direction without adriving connection in an overrunning effect. in the latter case, thefriction in the bearings 14 and other adjacent rotating elementspositioned between the inner and outer members will cause thetemperature of the lubricant and the surrounding air in the enclosure 33to rise and the lubricant to expand. Ordinarily, the expansion of thelubricant in the air in th chamber 33 will tend to force oil between theinner race sur face 35 and the seals 15 to cause rupture or leakage ofthe seals, and eventual loss of lubricant. However, in this invention,exp'andingbair in the enclosure 33 may escape through the'tnner race ypassing through slot 37, groove 35, radial passage 34 and longitudinalpassage 19 to the atmosphere to relieve the pressure within theenclosure. Similarly, air may be drawn from the atmosphere into theenclosure when the lubricant and air in the enclosure tend to contractclue to cooling oflof the clutch during less severe use.

It should be noted that the passage 341 is directed radially inward intothe keyway 19 so that centrifugal action during the relative rotationofthe inner and outer races 11 and 12 cannot cause lubricant to beforced through the passages 34 and 19. The lubricant will be forcedradially outward allowing only air to pass radially inward through thepassage 34. Also, inasmuch as the passage 34 is formed in the inner raceand extends radially inward and can only vent through the keyway 19which is not otherwise connected with the chamber 33, lubricant below acertain level in the cam clutch lubricant enclosure 33 will not run outof the enclosure under the force of gravity when the inner race 11 isstopped with the passage 34 in the down position which is opposite tothe position shown,

Further, it should be noted that groove 35 in the inner race 11 ispositioned entirely under the bearing 14 so that the only lubricant thatmay pass therein must pass through the slot 37. The slot 37 isnecessarily of substantially small circumferential dimension so thatsubstantially all the oil passing radially inwardly along the surface ofthe bearing 25 will flow over the surface 25 of the inner race member 11to the bottom of the clutch with only a chance of a minute amount of oilpassing into the slot 37 and out of'the clutch through keyway 19.

Thus, the present invention is provided with a lubricant enclosure ventby virtue of the novel inner race structure having a longitudinalpassage 19, passage 34, groove 35, and slot 37.

his to be understood that the invention is not to be limited to thespecific constructions and arrangements shown and described, as it willbe understood to those skilled in the art that changes may be madewithout departing from the principles of the invention.

lclaim:

l. A rotational device adapted to be mounted on a keyed shaft comprisinga first member having a passage formed therein for receiving the shaft,a second outer member positioned around said first member, bearing meansfor rotatably supporting said second member on said first member, andseal means extending between said first and second members for enclosingsaid hearing means between said first and second members, said firstmember having a keyway formed therein opening into the shaft passage andextending axially to the end of the first member, said first memberhaving a single annular groove formed in the periphery thereof andlongitudinally positioned entirely under one of said bearing means, saidfirst member having a radial passage formed therein in the bottom ofsaid annular groove at one peripheral point thereof adjacent said keywayand connecting said keyway and said groove, said first member having alongitudinal slot formed in the periphery thereof'and circumferentiallyspaced from the radial passage thereof and extending; longitudinallybeyond said bearing to communicate with the bearing enclosure.

